Mortar gun



Nov. 16, 1954 2,694,569

- MORTAR GUN Filed Oct. 12, 1950 I '1 Av INVENTOR.

LAWRENCE v \'\'A A TTORNE Y.

United States Patent MORTAR GUN Lawrence Vita, Smithtown Branch, N. Y.

Application October 12, 1950, Serial No. 189,732

8 Claims. (Cl. 222-324) This invention relates to mortar guns and is herein disclosed in the form of an easily portable device suitable for depositing mortar on hollow tile building blocks and for use in other building operations.

Cement guns have been suggested in the past for depositing cement mortar but have involved many objections and difliculties. As a result, workman laying, for example, a hollow tile wall, use an old fashioned trowel, lacking any power tool useful for decreasing fatigue or speeding up work.

One form of cement guns propelled the cement in one stream, the sand in another, and water in a third, so that the cement mortar would mix and set after leaving the gun. Cumbersome as that was, it seems to have been the most practical hitherto devised. Other forms mounted the nozzle so that the workman found the end obscured by the body of the gun.

Other forms were prohibitively difiicult to clean after use, and seem to be not commercially available.

According to the present invention the foregoing and other difliculties and objections are overcome and an easily handled, easily cleaned motor-driven mortar gun is provided adapted to feed mortar at a convenient yet rapid speed.

In the form shown the mortar is placed in an opentopped hopper and a bottom feed-screw feeds the motar through a horizontal bottom, easily visible nozzle.

The screw is shown as motor driven, and as removable as a unit with the motor, leaving the hopper open for easy cleaning, and the screw is easily cleaned as by dipping it while turned by the motor into a bucket of water.

It is found that a cement gun, thus constructed, need not weigh more than thirteen and onehalf pounds and yet carry a twenty-one pound charge of mortar, sufiicient to lay mortar on thirty feet of building block joints.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Fig. 1 shows the motor gun viewed from above;

F Fig. 2 shows it in side view section on the line 22 of P Fig. 3 shows it in end view section on the line 33 of The gun in the form shown includes a hopper body 10, open at the nearly rectangular top 11, and having vertical, or nearly vertical sides 12 at the top, bending inward to a nearly semi-circular trough-like bottom 13, but slightly steeper and more pyramidal than a true semi'circle. This form of bottom and lower sides provides a structure that rests securely between the upstanding ears of an upended standard hollow building block.

The front and back nearly flat ends 14 and 15 slope rearwardly as they rise, merging by curves into the sides, and the front end 14 near its bottom carries a horizontal projecting circular nozzle 16.

Close to the bottom curve 13, but preferably clearing it by something less than /s inch is shown a worm feed screw 17 which has been found satisfactory if an inch and a half in diameter.

The screw 17 is shown as projecting from bearings carried in a rearwardly projecting sleeve 19 shown as welded to the rear wall 15 at its bottom, so that the forward tapered end of the screw 17 projects into the tapered front extension 20 of the front wall 14, terminating just short of the nozzle 16, tapering down from about 1 /2 inches to clear the interior of the one inch round nozzle.

It is found that this taper, combined with a taper 21 of the shaft 22 of the screw within the extension down almost to a point, insures the even feeding of the stiff 2,694,509 Patented Nov. 16, 1954 mortar, eliminating air spaces which the stiif mortar woilllld otherwise leave in giving the mortar its final solid pus It is found that tapered extension 20 should present a smooth rounded curve 23 at its top where it merges into the front end 14 to ensure even flow of the mortar. Moreover its bottom slopes slightly upward to conform to the taper of the screw 17.

The sleeve 19 is shown as split at 24 so that it may be 0 tightened up by a headed screw 25 and firmly grasp the cylindrical bearing support 26 in which the shaft 22 is carried by bearings 27, 28, 29.

The bearing 28 is shown as a thrust bearing with a vertical annular race lying against the internal annular ledge 30 of the secondary bearing support 31 in which run balls that also run in the vertical annular race lying against an annular shoulder 32 on the shaft 22, thus absorbing the thrust of driving the mortar out of the nozzle 16.

The front bearing 27 of the shaft 22 includes a race 33 embracing the shaft 22 and an outer race 34 resting against an abutment 35 in the bearing support 26.

The rear bearing 29 of the shaft 22 includes a race lying against an abutment 36 in the secondary support 31 on which run balls also running on a race lying against an abutment 37 on the shaft 22.

There is also shown a bronze annular journal plate 38' lying around the shaft 22 at the abutment 35.

The bearing support 26 is shown extended as a split sleeve 39 adapted to be tightened by a headed screw 40 so as to grasp the secondary bearing support 31 and extension 41, and thus firmly hold the motor casing assembly 42 which is fastened to it.

The motor (not shown) within the casing 42, is adapted to drive the shaft 22 by a reduction gear, partly shown at 43, and is controlled by a trigger switch 44 forming a convenient part of a horizontal grip handle 45. The electric conductors are shown at 46.

Mortar and water are effectively kept away from the bearings 27, 28, 29, 38 by a disc 47 on the shaft 22 which holds a standard annular elastic Garlock seal 48 against the bearing race 27.

A workman fills the hopper body 10 with cement mix and then lifts the gun by the front handle 49, shown as welded to the interior of the front wall 14, and so projecting upwardly and rearwardly a few inches, and also seizes the rear handle 45 and applies the nozzle 16 to the upper edge of a hollow tile and starts the motor by the switch 44. It is found that a standard type of motor and reduction gear expels the cement at a convenient rate, so that a man with a gun works about three times as fast as a man with a trowel. It is also found rapid progress is made on vertical joints with standard setting by holding the nozzle 16 against a joint and slowly raising the gun while it forced the mortar into the joints.

The workman was easily able to see what he was doing because he easily saw the end of the nozzle over the retreating front wall 14, and the rolled over top 50 of the hopper body, rolled over the rod or wire 51, stiffens the hopper so that it was light and strong. So great was the speeding up of laying hollow tile that a workman paid for a gun in the time saved in a weeks work with it, and thus, if desired, it was not extravagant to build it out of aluminum or plastic, although these wore out more rapidly than iron or steel.

Having thus described one form of the invention in some detail, what is claimed is:

1. In a cement gun, a hopper having front and rear walls with the front wall rearwardly inclined, handles supported by said walls, a nozzle projecting nearly horizontally from the front wall near its bottom to a point where a workman behind the hopper and holding the gun by the handles sees the end of the nozzle over the front wall, and a feeding device within the hopper forcing mortar through the nozzle.

2. In a cement gun, a hopper having a front wall and a rear wall and a nearly horizontal bottom, a tapered nozzle projecting forwardly from the front wall adjacent the bottom of said front wall, a feed screw lying along the hopper bottom and projecting within the nozzle, a tapered end of the screws normally held substantially at the end of the nozzle, a tapered shaft carrying the screw and ending its taper in a point substantially at the end of the nozzle so the screw delivers a substantially solid stream of stiff mortar out of the nozzle, a sleeve in said rear Wall,

a journal for the shaft adapted to lie in the sleeve, and

a releasable holding device holding the journal in the sleeve.

3. In a cement gun, a hopper having front and rear walls, with the front wall rearwardly inclined, a handle on the front wall of the hopper, a nozzle projecting forwardly from the front wall adjacent the bottom of said hopper, to a point where a workman behind the hopper and holding the gun by the handle sees the end of the nozzle, a feed screw lying along the hopper bottom and projecting into the nozzle, a shaft carrying the screw, a sleeve in the rear hopper wall, a bearing carrying the shaft and fitting in the sleeve, a motor unit carrying the bearing and driving the shaft, and releasable means holding the bearing in the sleeve.

4. In a cement gun, a hopper having front and rear walls, with the front wall rearwardly inclined, a handle on the front wall of the hopper, a nozzle projecting forwardly from the front wall adjacent the bottom of said hopper, to a point where a workman behind the hopper and holding the gun by the handle sees the end of the nozzle, a feed screw lying along the hopper bottom and projecting into the nozzle, a shaft carrying the screw, a sleeve in the rear hopper wall, a bearing carrying the shaft and fitting in the sleeve, a motor unit carrying the bearing and driving the shaft, and releasable means holding the bearing in the sleeve, and a second handle for the workman forming part of the motor drive unit.

5. In a cement gun, a hopper having a front wall and a rear wall and a nearly horizontal bottom, a tapered nozzle projecting forwardly from the front wall adjacent the bottom of said front wall, a feed screw lying along the hopper bottom and projecting within the nozzle, a tapered end of the screw normally held substantially at the end of the nozzle, a tapered shaft carrying the screw and holding it clear of the hopper, and ending its taper in a point substantially at the end of the nozzle so the screw delivers a substantially solid stream of stiff mortar out of the nozzle, a sleeve in said rear wall, a journal for the shaft adapted to lie in the sleeve and a releasable holding device holding the journal in the sleeve.

6. In a cement gun, a hopper having front and rear walls with the front wall rearwardly inclined, a handle on the front wall of the hopper, a nozzle projecting from the front wall near its bottom and joining its top to the hopper by a smooth curve to a point Where a workman behind the hopper and holding the gun by its handle sees the end of the nozzle, a feed screw lying along the hopper bottom and projecting into the nozzle, a shaft carrying the screw, a bearing for the shaft, a sleeve in the rear wall of the hopper, and a device for releasably holding the bearing in the sleeve.

7. In a cement gun, a hopper having a nearly rectangular top, a front wall, a rear wall, both walls being rearwardly inclined, a rounded trough-like bottom in the hopper, a top handle carried by the front wall, a nozzle projecting nearly horizontally from the front wall near its bottom, a feed screw lying in the trough-like bottom and projecting into the nozzle, a sleeve in the rear wall, a shaft carrying the screw and projecting into the sleeve, and journals carrying the shaft and removably mounted in the sleeve.

8. In a cement gun, a hopper having a nearly rectangular top, a front wall, a rear wall, both walls being rearwardly inclined, a rounded trough-like bottom in the hopper, a top handle carried by the front wall, a nozzle projecting nearly horizontally from the front wall near its bottom, a feed screw lying in the trough-like bottom and projecting into the nozzle, a sleeve in the rear wall, a shaft carrying the screw and projecting into the sleeve, and a motor drive unit including journals carrying the shaft and holding the screw clear of the bottom, and removably mounted in the sleeve, and a second handle forming part of the motor drive unit.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,536,729 Richardson May 5, 1925 1,829,479 Elkins Oct. 27, 1931 FOREIGN PATENTS Number Country Date 123,733 Germany Sept. 20, 1901 

